Wellbore frac tool with inflow control

ABSTRACT

An apparatus for fluid treatment of a borehole includes: a tubular body having a long axis and an upper end, a first port extending through the wall of the tubular body, a second port extending through the wall of the tubular body, the second port having a fluid inflow control mechanism positioned to control the flow of fluid into the tubular body through the port, the first port being configurable from an open position to a closed position; and a controller to actuate the first port into the closed position, a set time after the first port is placed into the open position.

RELATED APPLICATIONS

This application claims priority to U.S. 61/533,660, filed Sep. 12,2011.

FIELD

The invention relates to a method and apparatus for wellbore fluidtreatment and, in particular, to a method and apparatus for selectivecommunication to a wellbore for fluid treatment and effectively handlingproduced fluids.

BACKGROUND

An oil or gas well relies on inflow of petroleum products. When naturalinflow from the well is not economical, the well may require wellboretreatment termed stimulation. This is accomplished by pumpingstimulation fluids such as fracturing fluids, acid, cleaning chemicalsand/or proppant laden fluids to improve wellbore inflow.

In one previous method, the well is isolated in segments and one or moresegments are individually treated so that concentrated and controlledfluid treatment can be provided along the wellbore by injecting thewellbore stimulation fluids from a tubing string through a port in thesegment and into contact with the formation. After wellbore fluidtreatment, the stimulation fluids are sometimes allowed to back flowfrom the formation into the wellbore tubing string. Thereafter, fluidsare produced from the formation. In some embodiments, the producedfluids also enter the tubing string for flow to the surface. Suchwellbore treatment systems are described in U.S. Pat. Nos. 7,748,460 and7,543,634 and PCT application PCT/CA2009/000599, to Packers Plus EnergyServices Inc.

It may be advantageous in certain circumstances to control the inflow ofproduced fluids. For example, it may be advantageous to screen theproduced fluids before they enter the tubing string. In addition oralternately, the produced fluids may require flow rate control, as byuse of chokes including devices called inflow control devices (ICD).

SUMMARY

In accordance with a broad aspect of the present invention, there isprovided an apparatus for fluid treatment of a borehole, the apparatuscomprising: a tubular body having a long axis and an upper end, a firstport extending through the wall of the tubular body, a second portextending through the wall of the tubular body, the second port having afluid inflow control mechanism positioned to control the flow of fluidinto the tubular body through the port, the first port beingconfigurable from an open position to a closed position; and acontroller to actuate the first port into the closed position, a settime after the first port is placed into the open position.

There is also provided a method for fluid treatment of a borehole, themethod comprising: running a tubing string into a wellbore to a desiredposition for treating the wellbore; opening an outflow port byapplication of a force to a sliding sleeve valve for the port; injectingstimulating fluids through the outflow port; closing the outflow portafter a selected time; opening the fluid inflow control portautomatically; and permitting fluid to pass from the wellbore into thetool through the fluid inflow control port.

It is to be understood that other aspects of the present invention willbecome readily apparent to those skilled in the art from the followingdetailed description, wherein various embodiments of the invention areshown and described by way of illustration. As will be realized, theinvention is capable for other and different embodiments and its severaldetails are capable of modification in various other respects, allwithout departing from the spirit and scope of the present invention.Accordingly the drawings and detailed description are to be regarded asillustrative in nature and not as restrictive.

BRIEF DESCRIPTION OF THE DRAWINGS

A further, detailed, description of the invention, briefly describedabove, will follow by reference to the following drawings of specificembodiments of the invention. These drawings depict only typicalembodiments of the invention and are therefore not to be consideredlimiting of its scope. In the drawings:

FIG. 1 is an axial sectional view through a wall of a well treatmenttubular in a run in condition;

FIG. 2A is a view of the well treatment tubular of FIG. 1 in a positionin a wellbore and opened for annular fluid treatment through thetubular;

FIG. 2B is a enlarged section through the check valve of FIG. 2A;

FIG. 3 is a view of the well treatment tubular of FIG. 1 in a positionclosed after the annular fluid treatment through the tubular;

FIG. 4A is a view of the well treatment tubular of FIG. 1 in a positionwith inflow occurring through the inflow port;

FIG. 4B is an enlarged section through the check valve of FIG. 4A;

FIG. 5 is an enlarged section through the check valve after being erodedby inflow;

FIG. 6 is a view of the well treatment tubular of FIG. 1 in a positionwith the inflow port being closed;

FIG. 7 is a view of the well treatment tubular of FIG. 1 being treatedto remove the ball seats; and

FIG. 8 is a view of the well treatment tubular of FIG. 1 with a fullopen bore.

DETAILED DESCRIPTION

The description that follows, and the embodiments described therein, isprovided by way of illustration of an example, or examples, ofparticular embodiments of the principles of various aspects of thepresent invention. These examples are provided for the purposes ofexplanation, and not of limitation, of those principles and of theinvention in its various aspects. The drawings are not necessarily toscale and in some instances proportions may have been exaggerated inorder more clearly to depict certain features. Throughout the drawings,from time to time, the same number is used to reference similar, but notnecessarily identical, parts.

A method and apparatus has been invented which provides for injecting ofa wellbore treatment fluid and then reconfiguration to control the flowof produced fluids. The apparatus and methods of the present inventioncan be used in various borehole conditions including open holes, casedholes, vertical holes, horizontal holes, straight holes or deviatedholes.

With reference to the drawings, the apparatus is a wellbore treatmenttubular with tubular body 10 having a long axis x extending from itsupper end 10 a to its lower end 10 b. An inner bore 12 is defined withinthe inner surface 10 c of the tubular body's wall. An outlet port 14extends through the wall providing fluid communication between innerbore 12 and an outer surface 10 d of the wall. A sliding sleeve 16 ispositioned in the wellbore treatment tubular to control the open andclosed condition of outlet port 14. In this embodiment, sliding sleeve16 is positioned in inner bore 12 and is moveable between a positionoverlying, and therefore closing, port 14 (FIG. 1) and a positionretracted from, and therefore opening, port 14 (FIG. 2). Sliding sleeve16 can move between the closed position and the open position byapplication of a force to move the sleeve. In this illustratedembodiment, force to move the sleeve is hydraulic. In this illustratedembodiment, sliding sleeve 16 includes a ball seat 18 on which a plugsuch as a ball 19 can be landed to create a seal and to allow ahydraulic force to be developed to push the sleeve along the inner bore.Sleeve 16 is normally held in a port closing position by a holdingmechanism 20, such as a shear pin, but can be moved if sufficient forceis applied to overcome the holding force of mechanism 20.

A reclosing sleeve 22 is also provided to reclose port 14. Whilereclosing of port 14 could be effected through a portion of sleeve 16(i.e. further movement of sleeve 16 to again overlie port 14), in thisembodiment reclosing sleeve 22 is a separate component from sleeve 16.Reclosing sleeve 22 is positioned in the wellbore treatment tubularinner bore 12 and is moveable between a position retracted from port 14(FIGS. 1 and 2) and a position overlying, and therefore reclosing, port14 (FIGS. 3 to 8). Sleeve 22 can move between the retracted position andthe reclosing position by application of a force to move the sleeve. Inthis illustrated embodiment, hydraulic pressure is employed to apply theforce. Seals 29, 29 a, 29 b ensure that pressure is harnessed to drivesleeve 22 and also prevent leakage through port 14.

In particular, in the illustrated apparatus, hydraulic pressure to movesleeve 22 is from a hydraulic chamber 23 a placeable in communicationwith fluid external to the tool, called hydrostatic fluid in the well.Sleeve 22 only moves to reclose port 14 after a selected time lapses,that selected time being counted from when port 14 is first opened.

In the illustrated embodiment, a sensor senses the movement of sleeve 16to open port 14 and the movement triggers a timer to count down toopening chamber 23 a to hydrostatic pressure, which acts against anisolated pressure, for example lower, atmospheric pressure, chamber 23 bto close sleeve 22. The sensor may include, for example, a magneticproximity switch such as may include a hall effect sensor 24 and amagnet 25, one of which is carried on the sleeve and the other of whichis installed on the tubular body. Hall effect sensor 24 may be incommunication with a processor such as circuit board 26. Circuit board26 and its power source 26 a may be installed in a protected chamber.Circuit board 26 may have a timer integrated therein that delays openingof sleeve 22 until after a selected time has lapsed after movement ofsleeve 16 is sensed by the sensor.

Sleeve 22 may be moved by flooding chamber 23 a with hydrostaticpressure against an atmospheric chamber 23 b. For example, a “holeopener” can be employed, which includes a small plug 27 held in aplugging position in an fluid supply inlet 28 to chamber 23. Plug 27 isheld in place by a holder, such as a high strength filament, such as forexample, a Kevlar™ string. In this embodiment, the high strengthfilament that holds plug 27 in place may be destroyed by burning, forexample, by powering a coil about the filament when it is desired todestroy the filament. For example, the “hole opener” can be actuated bysending a current through a conductor to the holder to release the plugfrom its plugging position. The current through the conductor burns theKevlar string releasing plug 27 and allowing the chamber 23 a to floodwith hydrostatic pressure from outer surface 10 d. While chamber 23 awas previously at a pressure similar to that of chamber 23 b, oncechamber 23 a is flooded, the greater pressure of chamber 23 a movessleeve 22 to cover port 14. It is noted that seal 29 a has a greaterarea than seal 29 b and thus the flooding of chamber 23 a creates aforce against seal 29 a greater than the force against seal 29 b andthis moves sleeve 22 to close port 14.

Sleeve 22 is normally held in the retracted position by a holdingmechanism 30, such as a shear pin, but can be moved if sufficient forceis applied to overcome the holding force of mechanism 30.

In the same segment of tubular body, or connected directly or indirectlythereto as shown, is a fluid inflow control mechanism including at leastone inflow port 38 and an inflow controller 40 for that port. Whileinflow port 38 and fluid treatment port 14 are shown positioned onseparate components and axially spaced, they may be otherwise configuredbut do provide for fluid outflow from inner bore and fluid inflow toinner bore from the same annular space. In some embodiments, tubularbody 10 may carry packers 41 that are settable to isolate the segment ofthe well accessed by ports 14, 38 from other segments of the well.

Inflow controller 40 controls in some way the inwardly directed flow offluids, which are those passing from outer surface 10 d to inner bore12. In this embodiment, inflow controller 40 includes a screen 42 and achoking orifice 44, better known as an Inflow Control Device (ICD),although controller may include one or the other or other inflowcontrolling components such as a labyrinth channel. In one embodiment,the inflow controller is adjustable and in one embodiment remotelyadjustable, such as while the apparatus is positioned downhole. The portmay include a restriction, as shown, if it is to function as an ICD.Alternately, the port may be fully open if it's only inflow controlfunction is as a sand screen.

Port 38 is controlled to open automatically when fluid pressure on theouter surface is greater than pressure in inner bore 12. For example,port 38 is normally closed but opens when production pressure builds upin the annulus 72. The pressure differential may be controlled bycontrolling tubing pressure and pressure in the annulus can build upwhen port 14 is closed. In one embodiment, for example, port 38 may havea check valve 46 installed therein that only allows fluid to enter thetubing but restricts fluid from traveling from the tubing inner bore 12outwardly toward outer surface 10 d. Port 38 is exposed in the innerbore 12, but check valve 46 prevents fluid from passing therethroughoutwardly. For example, check valve 46 and/or port 38 may carry sealsthat are forced together to seal flow through the ports. Alternately orin addition, port 38 may be formed with an inner diameter that tapersoutwardly, for example frustoconically, and check valve 46 may besimilarly frustoconically formed, for example, with a poppet 48 that isconically formed, tapering toward its outer end. When the pressuredifferential between the ends of the poppet is greater in the inner borethan that pressure at outer surface 10 d, poppet 48 is forced againstthe tapering surface defining port 38.

Check valve 46 may have a temporary installation, as shown, such that iteventually is rendered in operative, such that eventually the checkvalve doesn't have any effect in port 38 and port 38 may besubstantially fully open. For example, check valve 46 may be erodable,including for example poppet 48 or a support for the poppet. In theillustrated embodiment, poppet 48 is held in place by an erodable plate50 and a biasing spring 52. When erodable plate 50 is in place, poppet48 and spring 52 operate according to a flow checking mode in port 38.However, when erodable plate 50 sufficiently erodes away, the poppet andthe spring can fall out of port 38, leaving it unrestricted. Erodableplate 50 may have one or more openings therethrough to allow some flowof fluids therethrough, but that flow erodes by the erosive particulatecontent and/or force of the flow of the fluids. Plate 50 may be formedof materials able to withstand immersion in wellbore fluids but erodibleafter a period of time downhole or after a period of time with flowtherethrough. Plate 50 may be formed of materials softer than steel suchas mild steel, aluminum, plastic, etc.

A channel 54 is formed through inflow control mechanism 40 through whichfluid can pass from screen 42 to orifice 44 to port 38.

The inflow control mechanism may include a closing sleeve 56 to closeport 38. While closing of port 38 could be achieved by a portion ofsleeve 16 or sleeve 22 (i.e. further movement of one of these sleeves tooverlie port 38), in this embodiment closing sleeve 56 is a separatecomponent from the other two sleeves. Closing sleeve 56 for inflow port38 is positioned in the wellbore treatment tubular inner bore 12 and ismoveable between a position retracted from port 38 (FIGS. 1 to 4) and aposition overlying, and therefore reclosing, port 38 (FIGS. 6 to 8).Sleeve 56 can move between the retracted position and the reclosingposition by application of a force to move the sleeve. In thisillustrated embodiment, a tool, such as a shifting tool 60, is employedto apply the force. Shifting tool 60 engages sleeve 56, for example,through a landing profile 62, and can move the sleeve axially to overlieand cover port 38. Seals 64 may be provided to prevent leaks betweenbody 10 and sleeve 56. A releasable lock, such as a snap ring 66landable in glands 68 a, 68 b, may be provided to ensure that the sleeveis resistant to accidental migration, but is moveable when gripped andmoved.

In use, tubular body 10 may be connected into a string and run into awellbore, defined by wall 70. An annulus 72 is formed between wall 70and outer surface 10 d. Packers 41 may be set to create an isolatedsegment of the annulus to which both ports 14 and 38 communicate.

To fluid treat the wellbore, sleeve 16 is opened by dropping a ball 19to land on seat 18. Ball 19 and seat 18 act as a piston and pressure canbe increased uphole thereof to create a differential to drive the seatand the ball, and thereby sleeve 16 down. Port 14 is opened by movementof sleeve 16 and a fluid treatment, arrows F, can be undertaken throughport 14. Fluid treatment can include wellbore stimulation, such asfracturing. Port 14, being open, provides for substantially unrestrictedpassage of the fluid treatment to the wellbore.

This movement of sleeve 16 is sensed at the processor, since magnet 25moves away from hall sensor 24. A timed count down is then initiated bythe timer. The countdown time can be set when the tool is being preparedat surface and is a time suitable to allow the fluid treatment to becompleted and, if desired, any initial back flow.

Port 14 closes once the timer runs out. For example, once the time setby the timer has lapsed, a port closure release mechanism operates. Forexample, the “hole opener” can be actuated to allow fluid to drivereclosing sleeve 22 to close over port 14. In the embodiment, employingplug 27 and a Kevlar string as the hole opener, circuit board 26 maysend a current through a wire to the coil around the Kevlar string. Thecurrent burns the Kevlar string releasing the plug 27 from inlet 28 andallowing chamber 23 a to flood with hydrostatic pressure from annulus72. This moves sleeve 22 to close port 14. Thus a delay closingmechanism is provided for fracturing port 14, wherein port 14 can beopened, but will be automatically closed after a certain, set time haslapsed.

Once fracturing port 14 closes, port 38 will eventually openautomatically when the pressure of fluids outside the tubular overcomescheck valve 46. Once opened, the inflow of produced fluids, arrows P, iscontrolled. In this embodiment, the well is produced through filter 42and all proppant may remain in place after the frac. Screen 42 filtersthe fluid and keeps the sand particles out of tubing 10. It isbeneficial after the frac to keep the proppant in place, such that it isnot produced back to the surface. After passing through filter 42, thefiltered fluid then passes into the tubular inner diameter throughchannel 54, orifice 44 and port 38.

Check valve 46 allows the stimulation of the stage between packers 41through fracturing port 14 without that fluid passing outwardly throughinflow control port 38, such that the inflow controller 40 (i.e. screen42/orifice 44) are not damaged from fluids F injected out from innerbore 12. Once the stimulation is complete, fracturing port 14 is closed,and the well is allowed to produce. After production is initiated, checkvalve 46 opens and the fluid enters the tubing 10. The produced fluid Phas most of the sand and debris filtered out, but the small amount thatis left and the velocity of the fluid erodes out check valve 46 andeventually an unrestricted path is created through port 38 for the fluidto enter the tubing string.

FIG. 1 shows the tubular apparatus, including inflow controller (i.e.screen 42 and ICD 44) and port 38 and fracturing port 14 and the delaymechanism, in the run in condition.

A tubular string segment shown in the drawings includes inflowcontroller 40 connected above fracturing port 14. The inflow controllerdoesn't need to be threaded directly to the tube containing thefracturing port; it could be several 100 feet away as long as the inflowport and the fracturing port are in fluid communication along theoutside of the tubular. This generally means that the inflow port andthe fracturing port are in the same interval in the installed string,for example, between the same pair of packers 41 in a packer isolatedwellbore.

In FIG. 2, a launched ball 19 has just hit ball seat 18 and fracturingport 14 is opened with the fluid treatment exiting the port to stimulatethe formation. The proximity sensor senses the movement of sleeve 16 andstarts the timer. In this embodiment, for example, circuit 26, throughhall sensor 24, senses that the magnet, and thereby sleeve 16, has movedaway and starts the countdown as set in timer. The fluids of the fluidtreatment, including proppant, don't enter the sand screen through port38 since the check valve is held in place with the pressure from thefrac. A pressure differential develops between the ends of poppet 48,wherein the pressure in the inner bore is greater than the pressure atouter surface 10 d and poppet 48 is forced against the tapering surfacedefining port 38.

In FIG. 3, the predetermined time has run out on the timer and theholder has been released. The hydrostatic pressure has pushed sleeve 22down closing fracturing port 14. In this illustrated embodiment,according to the timer the circuit board has sensed that the time haslapsed and has completed the circuit to burn the Kevlar and to releaseplug 27 from its plugging position in inlet 28. Once the holder for theplug is removed, hydrostatic pressure pushes the plug through inlet 28into chamber 23 a and the chamber floods with fluid and sleeve 22 isdriven to close.

With port 14 closed, the pressure of the produced fluids can build up,as shown in FIGS. 4A and 4B, and eventually, check valve 46 opens andinflow, arrows P, proceeds through filter 42 and orifice 44. The inflow,arrows P, erodes the check valve until port 38 is fully open (FIG. 5),allowing the flow only to be restricted by the orifice. For example, asshown in FIGS. 4B and 5, after a short amount of time, erodable plate50, which retains poppet 48 in port 38, erodes away and the poppet andspring 52 fall out of the port.

If the stage starts to produce too much water and, thus, makes thisinterval uneconomic or if it otherwise of interest to close offproduction through that interval, port 38 can be closed by closingsleeve 56 moved by a shifting tool 60 (FIG. 6). Shifting tool may be astandard B shifting tool, as shown, or another type of shifting tool.The sleeve may be gripped by use of gland 62.

As shown in FIG. 7, if desired the operator can introduce a mill 80 andmill out seat 18 on the fracturing port sleeve 16 with ports 14, 38 openor closed. In FIG. 8, apparatus is shown with the ball seat milled outand ports 14 and 38 closed. Port 38 could be reopened by moving sleeve56 with a shifting tool to resume production, if desired. Sleeve 56 maybe formed recessed at least in part out of the diameter to be milledsuch that it retains its gland 62 and can be positively gripped formovement.

The previous description of the disclosed embodiments is provided toenable any person skilled in the art to make or use the presentinvention. Various modifications to those embodiments will be readilyapparent to those skilled in the art, and the generic principles definedherein may be applied to other embodiments without departing from thespirit or scope of the invention. Thus, the present invention is notintended to be limited to the embodiments shown herein, but is to beaccorded the full scope consistent with the claims, wherein reference toan element in the singular, such as by use of the article “a” or “an” isnot intended to mean “one and only one” unless specifically so stated,but rather “one or more”. All structural and functional equivalents tothe elements of the various embodiments described throughout thedisclosure that are know or later come to be known to those of ordinaryskill in the art are intended to be encompassed by the elements of theclaims. Moreover, nothing disclosed herein is intended to be dedicatedto the public regardless of whether such disclosure is explicitlyrecited in the claims. No claim element is to be construed under theprovisions of 35 USC 112, sixth paragraph, unless the element isexpressly recited using the phrase “means for” or “step for”.

1. An apparatus for fluid treatment of a borehole, the apparatuscomprising: a. a tubular body having a long axis and an upper end; b. afirst port extending through the wall of the tubular body; c. a secondport extending through the wall of the tubular body, the second porthaving a fluid inflow control mechanism positioned to control the flowof fluid into the tubular body through the port; d. the first port beingconfigurable from an open position to a closed position; and e. acontroller to actuate the first port into the closed position, a settime after the first port is placed into the open position.
 2. Theapparatus of claim 1 further comprising a first closure positionedrelative to the first port, moveable from a position closing the firstport to a second position placing the first port in the open positionand a second closure positioned relative to the first port, moveablefrom a position away from the first port to a position overlying thefirst port and placing the first port in the closed position and thecontroller actuates the second closure to move to the position overlyingthe first port after the set time.
 3. The apparatus of claim 2 whereinthe controller includes a sensor to sense when the first closure movesinto the second position.
 4. The apparatus of claim 1 wherein thecontroller includes a circuit including a timer.
 5. The apparatus ofclaim 2 wherein the second closure is driven by hydrostatic pressure. 6.The apparatus of claim 1 wherein the second port is normally closed andopenable automatically when pressure external to the tubular body isgreater than pressure internal to the tubular body.
 7. The apparatus ofclaim 1 wherein the second port resists flow outwardly therethrough fromthe tubular body.
 8. The apparatus of claim 1 further comprising a checkvalve in the second port, the check valve resisting flow outwardlythrough the second port from the tubular body and being openableautomatically when pressure external to the tubular body is greater thanpressure internal to the tubular body.
 9. The apparatus of claim 8wherein the check valve is temporary.
 10. The apparatus of claim 8wherein the check valve is erodable.
 11. A method for fluid treatment ofa wellbore, the method comprising: a. running a tubing string into awellbore to a desired position for treating the wellbore; b. opening anoutflow port by application of a force to a sliding sleeve valve for theport; c. injecting stimulating fluids through the outflow port; d.closing the outflow port after a selected time; e. opening the fluidinflow control port automatically; and f. permitting fluid to pass fromthe wellbore into the tool through the fluid inflow control port. 12.The method of claim 11 wherein closing the outflow port occurs after aselected time from the opening of the outflow port.
 13. The method ofclaim 11 wherein closing the outflow port includes automatically openinga closing sleeve to hydrostatic pressure to drive the closing sleeveover the outflow port.
 14. The method of claim 11 wherein opening thefluid inflow control port occurs automatically when a pressuredifferential is established wherein pressure external to the tubularbody is greater than pressure internal to the tubular body.
 15. Themethod of claim 14 wherein the pressure differential is established byclosing the outflow port.
 16. The method of claim 11 wherein permittingfluid to pass includes screening the fluid.
 17. The method of claim 11wherein permitting fluid to pass includes controlling the pressure ofthe fluid passing through the fluid inflow control port.